Minimally invasive surgical techniques have become popular in total hip arthroplasty (THA) procedures. Advantages include minimizing soft tissue damage, reducing recovery and healing time, and reducing the length of the patient's hospital stay. One version of a minimally invasive THA techniques is an “anterior approach” or “direct anterior approach” which uses, for example, a portal between the tensor fascia latae muscle and the rectus femoris muscle. An anterior approach can exploit the interval between those muscles for both acetabular and femoral preparation, allow for primary exposure of the hip joint capsule with minimization of muscle damage, limit incision length, and leverage other advantages. However, exposure of the proximal femoral intramedullary canal to prepare the canal for receipt of the femoral stem of a femoral implant can be problematic in a THA procedure using an anterior approach. For example, anatomical features of some patients, such as gut or muscle tissues and/or other anatomic structures, can present problems in accessing and preparing the femoral intramedullary canal via a short surgical incision.
In order to address these concerns, special instrument handles have been developed which may, in some instances, be provided with anterior and/or lateral offsets. Additionally, offset instrument handles reduce mobilization of the targeted bone required to gain access to the femoral intramedullary canal for shaping in preparation for a joint replacement implant such as a femoral stem. This advantage extends to all surgical approaches, and is not limited to a direct anterior approach. A bone shaping or cutting member, such as a broach or rasp, may be connected to the distal end of the instrument handle. The bone shaping member and the distal portion of the instrument handle is inserted through the incision, manipulated to avoid the gut or other anatomic structures by virtue of the anterior and/or lateral offsets, and the bone shaping member is inserted into the intramedullary canal of the femur to shape the canal for subsequent receipt of the femoral stem of a femoral implant.
Current surgical instrument handles configured for connection to bone shaping members are typically large and heavy, and separate instruments may be required for each of the right and left femurs. Consequent issues include those related to, among other things, logistics, inventory requirement, and expense. Additionally, the connection between the instrument handle and the bone shaping member may lack rigidity and may permit a degree of motion therebetween, thereby reducing control of the bone shaping member and also limiting visual and tactile feedback to the surgeon as to the fit of the bone shaping member within the femoral canal which would otherwise provide the surgeon with the ability to estimate the resulting tightness of fit of the femoral stem within the canal and to allow for easier removal of the bone shaping member from the canal subsequent to shaping.
Thus, there remains a need to provide an improved surgical instrument handle assembly for releasable connection to orthopedic shaping or cutting members for use in total hip arthroplasty. The present invention satisfies this need and provides other benefits and advantages in a novel and unobvious manner.